Sleeve enclosed coil

ABSTRACT

An electric coil assembly has a bobbin-wound coil of electrically conductive wire mounted within an insulating sleeve member having circumferentially spaced electric terminals on the outside of the sleeve member. The ends of the coil wire are electrically connected to the spaced electric terminals to allow energization of the coil. The bobbin-wound coil is retained within the sleeve member so as to have the insulating end covers of the bobbin located within the sleeve member on each end of the coil. The sleeve member has a lip formed at each end to retain the bobbin end covers inside the sleeve member thereby sealing the coil within the sleeve member. The coil assembly is made by alignably connecting the ends of the bobbin-wound coil through the inside of the sleeve member to the sleeve member terminals on the outside of the sleeve member, sliding the coil into the sleeve member so as to have the bobbin end covers inside of the sleeve member, and forming a lip on the ends of the sleeve member to trap the bobbin end covers and the bobbin-wound coil within the sleeve member.

United States Patent 1191 Roggenkamp et a1.

[541 SLEEVE ENCLOSED COIL [75] Inventors: George H. Roggenkamp, Salem;

Walter C. Ellis, Jr., Roanoke County, both of Va.

[73] Assignee: Eaton Corporation, Cleveland, Ohio [22] Filed: Nov. 19, 1973 21 Appl. No.2 417,169

[52] U.S. Cl. 336/90, 336/192 [51] Int. Cl H01f 15/10, HOlf 27/04 [58] Field of Search 336/192, 198, 208, 209, 336/90 [56] References Cited UNITED STATES PATENTS 840,531 l/l907 Walsh 336/192 1,872,369 8/1932 Sickle 336/192 X 2,067,576 l/l937 Mitscherling.... 336/209 X 2,132,833 10/1938 Quam 336/192 2,214,151 9/1940 Wagar 336/192 2,264,832 12/1941 Ensign 336/192 2,360,835 10/1944 Kongsted et al..... 336/209 X 2,421,444 6/1947 Tyne 336/192 X 2,471,869 5/1949 Gebel 336/192 2,488,468 11/1949 Dinion 336/192 FOREIGN PATENTS OR APPLICATIONS 130,467 2/1929 Switzerland 336/209 1451 Dec. 31, 1974 Primary Examiner-Thomas J. Kozma Attorney, Agent, or Firm-Teagno & Toddy [5 7] ABSTRACT An electric coil assembly has a bobbin-wound coil of electrically conductive wire mounted within an insulating sleeve member having circumferentially spaced electric terminals on the outside of the sleeve member. The ends of the coil wire are electrically connected to the spaced electric terminals to allow energization of the coil. The bobbin-wound coil is retained within the sleeve member so as to have the insulating end covers of the bobbin located within the sleeve member on each end of the coil. The sleeve member has a lip formed at each end to retain the bobbin end covers inside the sleeve member thereby sealing the coil within the sleeve member. The coil assembly is made by alignably connecting the ends of the bobbinwound coil through the inside of the sleeve member to the sleeve member terminals on the outside of the sleeve member, sliding the coil into the sleeve member so as to have the bobbin end covers inside of the sleeve member, and forming a lip on the ends of the sleeve member to trap the bobbin end covers and the bobbin-wound coil within the sleeve member.

7 Claims, 4 Drawing Figures SLEEVE ENCLOSED COIL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electric coils generally and particularly to electric coil assemblies wherein the coil is enclosed within a sleeve member having electrical terminals for energizing the coil.

2. Description of the Prior Art Electric coil assemblies are known wherein the coil is wound on a spool member or bobbin and the wound coil is then wrapped with an electrically insulating material.

Some electric coils are circumferentially wrapped with partially slitted insulating material having a width greater than the coil width. The slitted excess width of the insulating material is turned into the central opening of the bobbin to thereby cover the ends of the coil. The aforementioned coil construction is best described in US. Pat. No. 1,863,713, issued June 21, I932 to R. A. Connor.

Other electric coils are radially wrapped with a continuous strip of insulating material. The material is continuously extended through the central opening of the coil bobbin and around the coil windings with each succeeding turn partially overlapping the previous turn until the entire coil is enclosed by the insulating material.

Whether the winding is circumferential or radial, these prior art processes of enclosing the coil in insulating material are time consuming, costly, and do not easily lend themselves to mass-production techniques.

Furthermore, the resulting insulating cover for the coil is too weak to rigidly support electric terminals for energizing the coil.

Electric terminals, when present on the prior art wrapped coil assemblies are affixed to a contoured terminal board which is fitted to the coil contour and this terminal board is in turn affixed to the coil by the same wrapping used to enclose the coil. The coil wrapping material used to wrap the terminal board to the coil is generally not strong enough to properly strain relieve the terminal board which may be partially or totally dislodged from electrical contact with the coil if the electrical connections to the terminal board are strained.

SUMMARY OF THE INVENTION The present invention solves the aforementioned problems and others by providing a uniquely constructed electric coil assembly wherein an annular electric coil is enclosed within a tubular casing of insulating material.

The coil is made from a single electrical conductor which is wound around a bobbin to have a first and a second end. However, the coil could just as easily be made from a plurality of conductors. Electric terminal means are affixed on the outside of the tubular casing and the ends of the bobbin-wound coil are electrically connected to the terminal means to allow energization of the coil when it is mounted in the casing through the terminals on the outside of the casing. The ends of the coil are electrically insulated by the bobbin end covers which extend across the ends of the coil when the bobbin-wound coil is mounted within the casing.

The electric terminals for energizing the coil are mounted along a central circumference of the outside of the tubular casing to be substantially apart. The ends of the coil are similarly retained substantially 90 apart on the bobbin by taping one end to the outer periphery of the coil and retaining the other end between one bobbin end cover and an annular coil spacer mounted at one side of the coil to have a notch located along the inner opening of the coil spacer. The bobbin wound coil is mounted within the tubular casing to have the spaced coil ends and the spaced terminals substantially aligned. The end covers of the bobbin which insulate the ends of the coil are used to retain the coil inside the tubular casing by forming on the ends of the tubular casing to extend partially over the bobbin end covers.

The process of coil assembly includes the proximate aligning of the coil ends of the bobbin-wound coil with the electric terminals of the tubular casing and threading the coil ends from the inside of the tubular casing to the terminals on the outside thereof where the coil ends are welded to their respectively aligned terminal. The bobbin-wound coil is then slid entirely into the casing which has one preformed lip with the bobbin end covers positioned at each end of the casing. The other edge of the casing is then formed over the adjacent end cover to thereby provide a rim at each end of the casing to retain the coil within the casing.

Clearly, the present invention provides an electric coil assembly which is simple in construction and rugged in use. There is no need for the time consuming and costly wrapping with insulating material, as in the prior art coil assemblies, nor is there any problem of providing a rugged terminal board which will accept normal strain. The rigid casing of the present coil assembly allows the electric terminals to be affixed directly to the outside surface of the tubular casing which provides a rigid and strain relieved surface.

A feature of the present invention, therefore, is to provide a coil assembly wherein the coil is mounted within an enclosing sleeve member to be electrically insulated by the sleeve member.

Another feature of the present invention is to provide a coil assembly having a pair of terminals rigidly affixed to the outer circumference of the sleeve member to provide reliable electrical connections for the coil within the sleeve member.

These and other features of the present invention will be more apparent upon a review of the following description of the preferred embodiment in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the coil assembly of the present invention.

FIG. 2 is a perspective exploded view of the individual elements of the coil assembly of FIG. 1;

FIG. 2a is a detailed sectional view of the mounting of the electric terminals shown in FIG. 2.

FIG. 3 is a perspective view of the alignable mounting of the bobbin-wound coil within the casing.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, FIGS. 1 and 2 show an enclosed coil assembly 10 wherein a coil 28 is wound on a bobbin assembly 42 and encased within a rigid sleeve member I2 with end covers 14 and 16 of the bobbin assembly 42 being located at each end of the coil 28. The bobbin assembly 42, the end covers 14 and 16, as well as the sleeve member 12 are manufactured from electrically insulating material such as Fishpaper to thereby electrically insulate the entire coil 28 within the coil assembly 10. The coil 28 is electrically energized through a pair of spaced electrical terminals 18 and 20 which are located electrically connected to the coil 28.

The coil 28 is made by winding an insulated conductor around the bobbin assembly 42 to provide a plurality of conductor layers. The bobbin assembly 42 includes a spool member 43 having a pair of annular end covers 14 and 16 fitted over the spool 43 and retained thereon by turned edges 44 of the spool 43. An annular spacer 24 is also mounted on the spool 43 to fit loosely thereon between the end covers 14 and 16. A first end 30 of the conductor extends from the first conductor layer nearest the spool 43 of the bobbin assembly 42 and a second end 32 of the conductor extends from the last conductor layer furthest from the spool 43. The coil 28 is wound to have the annular spacer member 24 mounted at one end of the coil 28 and the first end 30 of the conductor extended through a notched section 26 located along the annular opening of the spacer 24 as is best seen in FIG. 3. The spacer 24 is made of an electrically insulating material, such as Fishpaper having a thickness of 0.015 inches, and thereby insulates the first'end 30 of the conductor from the side of the coil 28. The second end 32 of the conductor is retained in a position substantially 90 from the notched section 26 of the spacer 24 by tape 34 extending around the periphery of the coil 28. The tape 34 provides electrical insulation of the outer periphery of the coil 28 as well as retaining the second end 32 of the coil conductor. The sleeve member 12 is formed from a rigid cylindrical section of electrically insulating materiaL'such as Fishpaper having a thickness of 0.03l inches, which provides a strong strain relieved mounting for the terminals 18 and 20. The sleeve member 12 is cylindrical but has a lip 45 formed at one end to initially retain the bobbin-wound coil 28. As is best seen with reference to FIG. 2a, the terminals 18 and 20 of the sleeve member 12 are riveted along the central circumference of the sleeve member 12 by rivets 40. The terminals 18 and 20 are spaced90 to provide a single side electrical connection of the coil assembly to a power source (not shown). Each of the rivets 40 have a passageway 22 large enough to thread the first end 30 or the second end 32 of the coil conductor therethrough.

The method whereby the bobbin-wound coil 28 is assembled to the sleeve member 12 is best explained with particular reference to F IG. 3. The bobbin-wound coil 28 with the first end 30 and the second end 32 retained at the 90 spacing is aligned with the sleeve member 12 to have the first end 30 and the second end 32 of the coil conductor respectively aligned with the terminals and 18. The first end 30 of the coil conductor is extended from the inside of the sleeve member 12 through the passageway 22 of the rivet 40 to the terminal 20. The second end 32 of the coil conductor is then similarly extended to terminal 18. The bobbin-wound coil 28 is then completely inserted into the sleeve member 12 to fit against the edge 45. The sleeve member 12 is wider than the coil 28 and provides an overlapping section at one end of the coil 28. With the coil 28 inside the sleeve member 12, any slack in the conductor ends 30 and 32 is picked up and they are soldered to their respective terminals 18 and 20 to provide electrical contact from the terminals 18 and 20 to the coil 28. The overlapping end of the sleeve member 12 is then rolled over to form rolled edge 36 which along with formed edge 45 overlaps over the end covers 16 and 14 to capture the bobbin-wound coil 28 within the sleeve member 12. The opening in thespool 43 is predetermined to allow the coil assembly 10 to be inserted over a core member (not shown) which fits through the openings of the spool 43. The end covers 14 and 16 as well as the spool 43 are made from an electrically insulating material, such as F ishpaper having a thickness of 0.045 inches, and effectively insulate the sides of the coil 28 not covered by the sleeve member 12.

Certain modifications and improvements will occur to those skilled in the art upon reading this disclosure. Clearly the terminals could be differently aligned on the sleeve member or even moved to one of the end covers. All such modifications and improvements are not included herein for the sake of conciseness and clarity but it is intended that such improvements and modifications fall within the scope of the claims and that they not be limited to the disclosed preferred embodiment.

We now claim:

1. An enclosed electric coil assembly comprising:

an annular coil wound around a bobbin to form a conductive member having a first end and a second end;

a rigid tubular casing of electrically insulating material extending longitudinally around the outer periphery of said coil to provide a sturdy mounting surface;

electric terminal means mounted to the outside of said rigid tubular casing, means electrically connecting at least one end of the conductive member of said annular coil to said electric terminal means at the point of attachment of said electric terminal means to said tubular casing, said end extending from the inside of said tubular casing to said terminal means, said tubular casing taking up any strain placed on said terminal means to prevent said conductive member from being disconnected from said terminal means; and

end cover means insulating the ends of said annular coil.

2. An enclosed electric coil assembly as set forth in claim 1 wherein said electric terminal means includes a pair of spaced electric terminals affixed to the outside surface of said tubular casing and having the first end of the conductive member electrically connected to one of said pair of terminals and the second end of the conductive member electrically connected to the second terminal of said pair of terminals to prevent any strain on said spaced electric terminals from being transmitted to said conductive member.

3. An enclosed electric coil assembly as set forth in claim 2 wherein said pair of electric terminals are spaced substantially at around a central circumference of said tubular casing.

4. An enclosed electric coil assembly as set forth in claim 3 including means for spacing the first end of the conductive member of said annular coil substantially 90 from the second end of the conductive member.

5. An enclosed electric coil assembly as set forth in claim 4 wherein said spacing means includes:

a tape member attached to the outer periphery of said annular coil to retain the first end of the conductive member at a stationary position along the outer periphery of said annular coil; and a spacer sheet having a notched annular opening therein and being mounted at one end of said coil to retain the second end of the conductive member between the notched section of the annular opening and said end cover means, said spacer being mounted to have the notched section spaced substantially 90 from the stationary position of the first end of the conductive member. 6. An enclosed electric coil assembly as set forth in claim 5 wherein the first end of the conductive member of said coil is substantially aligned with the first terminal of said pair of electric terminals of said tubular casing and the second end of the conductive member is substantially aligned with the second terminal of said pair of electric terminals.

7. An enclosed electric coil assembly as set forth in claim 6 wherein said end cover means includes a first end cover having one end of said tubular casing partially rolled over said first end cover and a second end cover opposite said first end cover and having the other end of said tubular casing partially roller over said second end cover. 

1. An enclosed electric coil assembly comprising: an annular coil wound around a bobbin to form a conductive member having a first end and a second end; a rigid tubular casing of electrically insulating material extending longitudinally around the outer periphery of said coil to provide a sturdy mounting surface; electric terminal means mounted to the outside of said rigid tubular casing, means electrically connecting at least one end of the conductive member of said annular coil to said electric terminal means at the point of attachment of said electric terminal means to said tubular casing, said end extending from the inside of said tubular casing to said terminal means, said tubular casing taking up any strain placed on said terminal means to prevent said conductive member from being disconnected from said terminal means; and end cover means insulating the ends of said annular coil.
 2. An enclosed electric coil assembly as set forth in claim 1 wherein said electric terminal means includes a pair of spaced electric terminals affixed to the outside surface of said tubular casing and having the first end of the conductive member electrically connected to one of said pair of terminals and the second end of the conductive member electrically connected to the second terminal of said pair of terminals to prevent any strain on said spaced electric terminals from being transmitted to said conductive member.
 3. An enclosed electric coil assembly as set forth in claim 2 wherein said pair of electric terminals are spaced substantially at 90* around a central circumference of said tubular casing.
 4. An enclosed electric coil assembly as set forth in claim 3 including means for spacing the first end of the conductive member of said annular coil substantially 90* from the second end of the conductive member.
 5. An enclosed electric coil assembly as set forth in claim 4 wherein said spacing means includes: a tape member attached to the outer periphery of said annular coil to retain the first end of the conductive member at a stationary position along the outer periphery of said annular coil; and a spacer sheet having a notched annular opening therein and being mounted at one end of said coil to retain the second end of the conductive member between the notched section of the annular opening and said end cover means, said spacer being mounted to have the notched section spaced substantially 90* from the stationary position of the first end of the conductive member.
 6. An enclosed electric coil assembly as set forth in claim 5 wherein the first end of the conductive member of said coil is substantially aligned with the first terminal of said pair of electric terminals of said tubular casing and the seconD end of the conductive member is substantially aligned with the second terminal of said pair of electric terminals.
 7. An enclosed electric coil assembly as set forth in claim 6 wherein said end cover means includes a first end cover having one end of said tubular casing partially rolled over said first end cover and a second end cover opposite said first end cover and having the other end of said tubular casing partially roller over said second end cover. 